Unique spawning behaviour by the Antarctic limpet Nacella (Patinigera) concinna (Strebel, 1908)

The Antarctic limpet Nacella (Patingera) concinna (Strebel, 1908) forms temporary “stacks” before spawning, a behaviour which ensures that gametes are released in close proximity. This promotes the fertilization of a large proportion of eggs, so reducing the energy outlay necessary to ensure reproductive success. The annual reproductive output of Nacella is low in comparison with other Patellidae. Rapid fertilization may also help to contain larvae in shallow coastal waters suitable for settlement. Evidence of this unique spawning behaviour has now been obtained in a series of photographs taken at Signy Island, South Orkney Islands (60°S : 43°W).